ANGIOSPERM^E 



381 



The Fruit 



The fruit of the Monocotyledons may be a dry capsule (Lilium), or 

 achene (Sagittaria), or caryopsis (most Grasses), or it may be a 

 pulpy berry (Asparagus, Smilacina, most Aracese), or a stone-fruit 

 like the Date, Cocoanut, and other Palms. Pseudo-fruits occur in 

 some Bromeliaceae, notably the 

 Pineapple, where the edible part 

 of the fruit is derived from the 

 enlarged floral axis and perianth. 



Classification of Monocotyledons 



The Monocotyledons may be di- 

 vided into the following orders : 



I. 

 II. 



Order 

 Order 

 Order III. 

 Order IV. 

 Order 

 Order 



V. 

 VI. 

 Order VII. 

 Order VIII. 

 Order IX. 

 Order X. 



Helobiese (Fluviales). 



Pandanales. 



Glumiflorae. 



Principes. 



Synanthae. 



Spathiflorae. 



Liliiflorae. 



Farinosae. 



Scitamineae. 



Microspermae. 



Order I. Helobieae (Fluviales) 



The Helobiese (Figs. 354, 355) are 

 aquatic plants, mostly of simple struc- FIG. 354. A, Zannichellia palustris, 



section of $ inflorescence surrounded 

 by the cup-shaped involucre, in 

 (X40). B-E, Potamogeton sp. B, 

 shoot with inflorescence (x 1). C, 

 single flower, enlarged. D, the same, 

 with the four scales removed to show 

 the stamens and pistil. E, four nearly 

 ripe fruits. 



ture. They may be completely sub- 

 mersed with slender stems and delicate 

 leaves (Naias, Zannichellia, species of 

 Potamogeton), or the plant may be 

 rooted in the mud, the leaves floating 

 at the end of slender petioles (Limno- 

 charis, Potamogeton natans, etc.). A 

 third type is that found in Lilsea, Tri- 

 glochin, Alisma, etc., where the short stem is rooted in the mud, and sends 

 up the rigid leaf-stalks and scapes above the surface of the shallow water in 

 which they usually grow. 



The leaves are linear, with broad sheathing base and axillary scales in the 

 completely submersed forms, rigid and awl-shaped like those of Isoetes in Lilsea 

 and Triglochin, with broad lamina and long petiole in Limnocharis, Alisma, and 

 Sagittaria. In the latter forms the leaves are often reticulately veined, suggest- 

 ing certain of the Dicotyledons, with which these forms have other points in 

 common. 



